The invention relates generally to an ink cartridge and a method of charging ink into the cartridge and more specifically to an ink cartridge and a method of charging ink into the cartridge suitable for an ink jet printer in which a carriage carries an ink jet recording head and an ink cartridge and in which the ink is replenished by replacing the cartridge.
In an ink jet printer in which the carriage carrying the ink jet recording head also carries an ink container, measures are taken to prevent pressure fluctuations of the ink due to the oscillation of the ink caused by the movement of the carriage, and defective printing due to foaming. That is, as proposed in Laid-open European Patent Publication No. 581531, the ink container of an ink jet printer is divided into two regions. A porous body is accommodated in a region on the recording head side, and ink is contained in the other region.
Such structure is advantageous in obviating inconvenience caused by the oscillation of the ink to a possible extent since the ink is supplied to the recording head through the porous body.
However, the porous body functions merely as a filter, and this means that it is the ink within the ink chamber, not the ink in the porous body that substantially is the remaining amount of ink. Therefore, when the ink within the ink chamber runs out, the printer can no longer print. In addition, in a color printer or the like that uses inks of a plurality of colors, the amounts of remaining ink vary from one ink chamber to another even if the inks of all the colors have been supplied simultaneously since all the inks are not necessarily consumed equally in color printing. As a result, ink remains within the cartridge in liquid form when the cartridge is replaced, and when the cartridge is discarded the ink may leak out and contaminate the environment. In addition, the user may unnecessarily become apprehensive over unbalanced consumption of ink and the possibility of one of the colors running out.
Generally speaking in accordance with the invention, an ink cartridge for an ink jet printer is provided. The ink cartridge includes: an ink chamber for retaining liquid ink; a foam chamber maintained in fluid communication with the ink chamber through a communication hole; and an ink supply port formed in a wall of the ink cartridge. A porous body for absorbing ink is accommodated in the foam chamber. The ink cartridge supplies the ink within the ink chamber to a recording head via the porous body and the ink supply port. The porous body is compressed in at least a region of the porous body confronting the ink supply port so that the compression ratio in the vicinity of the ink supply port becomes high. The ratio between the amount of ink initially charged in the ink chamber and that of ink absorbed in the porous body is in the range from 1:1 to 1:3.
Accordingly, it is an object of the invention to provide an ink cartridge capable of avoiding environmental pollution and unnecessary apprehension on the part of the user by totally absorbing all of the ink remaining in the cartridge in liquid form at the time of replacing the ink cartridge in the porous body.
Another object of the invention is to provide an ink cartridge capable of preventing leakage of the ink to the outside by causing all the ink to be absorbed in the porous body at the time of discarding the cartridge.
A further object of the invention is to provide an ink cartridge capable of relating the timing at which the ink within the ink chamber runs out to an indication to the user of a xe2x80x9cnear endxe2x80x9d condition.
Yet another object of the invention is to propose a method of charging the ink suitable for the aforementioned ink cartridge.
Still other objects and advantages of the invention will in part be obvious and in part be apparent from the specification.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.